Dr Sam Whiteford BSc, PhD

Postdoctoral Research Associate Evolution, Ecology & Behaviour

Research

Evolution of sex-determination systems

During my PhD with Alistair Darby, I had the opportunity to investigate the genetic basis of sex-determination in the diamondback moth (Plutella xylostella), an agricultural pest of cruciferous vegetables, using computational and functional methods (and a healthy dose of sequencing data). This was intended to inform efforts to develop novel methods of transgenic pest control alongside an industrial partner Oxitec Ltd. Over time I developed an appreciation of the deeper questions around the evolution of sex determination systems, particularly their diversity. For me, this is best encapsulated by the title of a 2014 review The Tree of Sex Consortium - "Sex Determination: Why So Many Ways of Doing It?".

At the time of studying, it was already clear from studies in the silkworm (Bombyx mori) and lepidopteran cytogenetics, that even within this sub-group of organisms a diverse range of sex-determination mechanisms are present. From the end of my PhD to the present, I've been able to contribute to studying a seemingly very unique and unusual lepidopteran sex-determination system, which we hope to share with the world very soon!

Ecological genetics of lepidopteran wing patterns

Anyone familiar with moths and butterflies will appreciate the aesthetic beauty and diversity of their wing patterns. My time with Ilik Saccheri has given me the opportunity to work with the famous peppered moth and help to address new questions about the complexity of melanism and atypical wing-pattern polymorphism in European populations. For example: What are the ecological drivers that can support or generate a large number of diverse phenotypes? Can we begin to measure the precise relationship between these drivers and genotypes explicitly? For me (and I hope others), the ability to bring new perspectives and technologies to bear on unresolved observations of our predecessors is particularly rewarding. The work of early lepidopterists provide a perhaps under-utilised abundance of ecological and phenotypic data (thanks in part to their aesthetic attraction). As in the case of the carbonaria mutation, these classic observations and collections can still yield great insights into fundamental evolutionary processes.

Genomics of non-model organisms

A large chunk of my time has been spent immersed in various types of 'omics' (particularly genomic) data. I suppose this is more of a technical interest than a research interest, as my exposure has largely involved grappling with the technical challenges of working with the ever-changing types (and combinations) of sequencing data being generated by a very fast-moving field. In short, how can we reconstruct a genome in an automated way with little a priori knowledge? How can we validate these reconstructions and what are the limitations of the current approaches?